Solar attachment for transit instruments.



Patented July 29, I902.

0. F. SHATTUCK.

SOLAR ATTACHMENT FOR TRANSIT INSTRUMENTS.

'Applicatiun filed Nnv. 14, 1901.) (No Model.) 2 Sheets$heet I.

INVENTOR.

M/ I WITNESSES: fici 6 7 l I '3 L 1 L 5 C find/e fdfia/fuc/r M. A I C Q0 0 c B}, I

40 I I/I I ATTORNEY.

m: Norms PETERS co, morou'rum w summon. nv c No. 705,970. Patented July29, I902.

0. F. SHATTUCK.

SOLAR ATTACHMENT FOR TRANSIT INSTRUMENTS.

(Application filed Nov. 14, 1901.)

(No Model.) 2 Sheets8heet 2.

v9- Br ,1 @Wa/ v ATTORNEY.

'm: NORRIS PETERS co. PHOYO-LITHQ. WASHINGTON, u c.

UNITED STATES PATENT OFFICE.

ORVILLE F. SHATTUOII, OF DENVER, COLORADO.

SOLAR ATTACHMENT FOR TRANSIT INSTRUMENTS.

SPECIFICATION forming part of Letters Patent N 0. 705,970, dated July29, 1902.

Application filed November 14, 1901. Serial No. 82,298. (No model.)

To all whom, it may concern:

Be it known that I, ORVILLE F. SHATTUCK, a citizen of the United Statesof An1erica,residing at Denver, in the county of Arapahoe and State ofColorado, have invented certain new and useful Improvements in SolarAttachments for Transit Instruments; and I do doclare the following tobe a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same, reference being had to the accompanying drawings, and to theletters and figures of reference marked thereon, which form a part ofthis specification.

My invention relates to improvements in solar attachments for transit,theodolite, or similar instruments, the object being to facilitate thefinding of the true meridian with instruments of this class.

My improved device may be readily applied to and detached from theobjective extremity of the telescope of any instrument of this characterWithout change or alteration in the construction of the latter.

The effectiveness of my improvement is dependent on the opticalprinciple that a ray of light which suffers reflection twice in the sameplane makes after its second reflection an angle with its originaldirection equal to twice the angle between the reflecting-surfaces. Bythe use of this principle the accuracy of the results is not dependenteither upon the precise adjustment of the attachment with reference tothe instrument nor upon the exactness of the construction of the solarattachment itself, but upon the maintenance of a given angle between thereflectors during an observation.

Having briefly outlined my improvement, the principle upon which itoperates, and the object sought to be attained thereby, I will proceedto describe the same in detail, reference being made to the accompanyingdrawings, in which is illustrated an embodiment thereof.

In the drawings, Figure -l is a side elevation of a transit instrumentequipped with my improved solar attachment. Fig. 2 is a centralverticalsection taken throughthe attachment, its parts being shown on alarger scale. Fig. 3 is a section taken on the line 1 1 Fig. 1.

Fig. 4 is a cross-section taken on the line 00 m, Fig. 2. Fig. 5 is aface view of the graduated head of a differentially-threaded nut tofacilitate theproper adjustment of the angle between the reflectors.Fig. 6 is a plan view of the horizontal limb of a transit instrumentshown on a smaller scale than in Fig. 1. Fig. 7 is a diagrammatic viewillustrating the use of the attachment. Figs. 8 and9 illustrate theposition of the sun in the reticule of different instruments. The imageof the sun is represented by a circle designated S in these views.

The same reference characters indicate the same parts in all the views.

Let A A designate the standards or parallel side pieces of abracketwhose base is attached by screws to a flanged journal K, which revolveson the base-plate L. To a ring L, which is set into the base-plate, isattached a clamping device M and a curved lug M. The latter is providedwith teeth or threads engaging the threads of a slow motiontangent-screw N, the extremities of which are journaled in the standardsA A. The baseplate L is attached to thetelescope in any convenientmanner to occupy a position beyond the objective of the instrument.Preferably it is fastened to a cap P, which fits over the objective endof the telescope, by means of screws with capstan-heads P and P', whichpass through plain openings in the base-plate L and are threaded intothe end of the cap P, while other screws P and P" are threaded in thebase-plate L and bear against the end of the capP. A reflector H issecurely attached to the parts A A in front (see Figs. 2 and 3) at suchan angle that'the rays of light from the objective 0 are reflectedtoward a second reflector I, pivotally attached to one side of thestandards A A, by means of a pivot B, about which the reflector movesupon turning a screw D. My experiments indicate that the best resultsare attained by placing the reflector H at an angle of sixty-sevendegrees and thirty minutes with the line of sight 0 O O of theinstrument. (In this description the rays of light are traced backwardout of the telescope to the reflectors, 850.)

The pivot B and the reflector I are placed perpendicular to a planewhich is perpen dicular to the reflector II and passes through -ICO theline of collimation O .C. This plane is called the plane of the solar.

The extremity of the screw D .remote from its head is reduced in size,forming a shoulder which rests against a lug E, mounted on the parts AA. A clamp-nut D, which is applied to the reduced end of the screw D andengages the lug E on the opposite side from the shoulder of the screw,may be employed to lock the screw in any desired position of adjustment.

The reflectorI is susceptible of a more delicate movement than can beaccomplished by the screw D. This, as shown in the drawings, (see Fig.2,) is accomplished by means of a difierentially-threaded nut D, whichcooperates with the screw D. The not D is provided on the inside withthreads of a certain pitch-say fifty-six threads to the inch fitting thethreads on the screw D, while on the outside of said nut the threads areof slightly-diiterent pitchsay fifty-two threads to the inch. The nut-Dis arranged to turn in a fixed nut D, which is attached to the plate orarm I, carrying the reflector I. With this arrangement and pitch of thethreads on the nut D and with a perpendicular distance of ninety-fourhundredths of an inch from the axis of the screw D to the pivot B onerevolution of the nut D" changes the angle between the line of sight 0 CO and the second reflected ray I T (see Figs. 2 and 7) ten minutes ofarc. The head of the nut D" is therefore graduated or divided into ten'equal parts. (See Fig. 5.) An index F is attached to the plate I and isheld by a spring 1 against the periphery of the head of the screw D". Asthe graduations are turned past the index F each division corresponds toa change in the direction of the second reflected ray I T of one minuteof arc. The index F, pressing against the milled head of the nut D, alsoacts as a stop or clamp to the motion of the nut when it is not in use.

The lost motion of the screw D and the nut D- is overcome by thetorsional action of a spiral spring G, coiled around the pivot B betweenthe standards A A. One extremity of this spring bears against the plateI holding the reflector I, and therefore actuates the reflector in thedirection indicated by the arrow in Fig. 1.

To provide for the passage of light from the reflector H to theobjective 0, an opening is made through the base of the standards A A atB through the journal K at R and through the cap P at R. I

To adapt this solar attachment to the cocentricities of any instrument,a level Q, attached to one of the standards A,is employed. This level islocated at right angles to the axis of the journal K. By using the leveland the adjusting-screws P, P, P", and P" the-axis of thejournal K maybe made parallel to the line of sight or collimation O G 0 when thetelescope is pointed to the zenith. A high degree of accuracy in thisadjustment is not required on account of the use in this solar of theoptical principle above stated.

To determine the true meridian by means of the double-reflecting solar,heretofore described, the surveying or astronomical instrument isleveled and the usual adjustment made. On the horizontal limb W of theinstrument the vernier V is set at an angle equal to ninety degrees plusor minus the suns declination, corrected for refraction, according 'towhether the sun is northvor south of the celestial equator. In this case(see Fig. 7) it is assumed that the sun is five degrees north and thevernier is set at ninety-five degrees. Without changing the readingofthe vernier the telescope 5 in a horizontal position is sighted at thetarget T. The cap P, carry ing the solar attachment, is placed in itsposition about the objective and the instrument is turned about itsvertical axis until the vernier of the horizontal limb is set at zero.With the telescope still in a horizontal position and the vernierclamped at zero, the center of a target T is brought into the sight-lineof the telescope by turning the screw D, the target T being so placedthat the distance T T equals the distance from the center of theinstrument 0 to the center of the reflector I. The screw D is thenclamped in this position by means of the nut D. Then the angle H H I(see Fig. 7 between the reflectors H and I is fortyseven degrees andthirty minutes and the angle between the original ray 0 H and the secondreflected ray I T is twice that amount, or ninety-five degrees, and willremain at ninetyfive degrees in whichever direction the reflectors maybe turned, so long as the angle between them remains at forty-sevendegrees and thirty minutes. Then set off the latitude of the place ofobservation on the vertical limb or are by depressing the object end ofthe telescope, still carrying the cap Pand solar. With the vernier V ofthe horizontal limb W still at zero the telescope is pointedapproximately south and the image of the sun brought into the field ofview by turning the solar upon its journal K, which is then clamped withthe clamp-screw M. Having also set the clamp 6 of the horizontal limb,the center of the suns image is brought to the center of the reticule(see Fig. 9) by turning the tangent-screw N and the tangent-screw 7 ofthe limb of the instrument. The telescope then points due south and theinstrument is in the meridian. The solar becomes an equatorialinstrument, which revolves about the I .oule similar to the one shown.in Fig. 9, but

instead single vertical and horizontal crosswires, the correcteddeclination set off in the solar, as above described, is also correctedfor the suns semidiameter multiplied by the cosine of the hour angle ofthe sun at the time of observation and the suns image brought into theposition shown in Fig. 2, which can be done with great precision.

Should it be desired to make other solar observations later in the day,it is not necessary to reset the proper angle inthe solar attachment byobserving terrestrial objects, as described above, but simply by turningthe nut D as many divisions or graduations as are required by the hourlychange in the suns declination and refraction.

If it is preferred, the same results may be obtained by setting off inthe solar attachment declination angles complementary to those abovedescribed, elevating the telescope to point to the north end of thepolar axis instead of the south, and proceeding as above.

As to the mechanical arrangement of the reflectors in this solarattachment, there are several other positions in which the reflectors Hand I may be placed and similar results obtained, but in each case theprinciple involved is the same. The positions that I have adopted permitof a more compact construction of the attachment than any of the others.The same is true of the differential threads. A differential nut is usedinstead of a difierential screw, the former being more compact and theprinciple being the same in both.

Having thus described my invention, what I claim is 1. In a solarattachment for transit, theodolite or similar instruments, thecombination with the telescope, of two reflectors mounted to rotateabout the objective extremity of the telescope while the latter remainsstationary, and arranged to reflect a ray of lighttwice, substantiallyas described.

2. In an instrument of the class described, the combination with thetelescope, of a bracket revolubly mounted on the objective extremity ofthe instrument and composed of two parallel side pieces, two reflectorsmounted between the parallel members of the bracket and arranged toreflect a ray of' light twice before entering the objective of thetelescope. Y

3. In an instrument of the class described, the combination with thetelescope, of a bracket revolubly mounted on the objective extremity ofthe telescope and composed of two parallel side pieces, and tworeflectors mounted between the sides of the bracket, one being fixed andthe other movable to vary the angle between them, substantially asdescribed.

4:. The combination with the telescope of a transit, theodolite orsimilarinstrument, of areflector-holder revolubly mounted on theobjective extremity of the telescope, two reflectors mounted on saidholder and turning therewith, the reflectors being arranged at suitableangles to each other'to reflect a ray of light twice, suitable meansforregulating one of the reflectors to vary their angle, and

suitable means for rotating the reflectorholder on the telescope,substantially as described.

5. The combination with the telescope of a transit, theodolite orsimilar instrument, of a reflector-holder revolubly mounted on theobjective extremity of the telescope, two reflectors mounted on saidholder and turning therewith, the reflectorsbeing arranged at suitableangles to each' other to reflect a ray of light twice, the secondreflection being in the line of the optical axisof the telescope, andsuitable means for regulating one of the reflectors to vary their anglesfor the purpose set forth.

6. The combination with the telescope of a transit or similarinstrument, of a reflectorholder revolubly mounted on the objectiveextremity of the telescope, two reflectors mounted on said holder andarranged to twice reflect a ray of light, the second reflection'be-- ingin line of the optical axis of the telescope,

one of the reflectors being pivotally mounted, and adifferentially-threaded nut mounted to regulate the position of thepivoted reflector for the purpose set forth. 7

7 The combination with the telescope'of a transit or similarinstrument,of a bracket revolubly mounted to project beyond theobjective of the telescope, two reflectors mounted on said bracket, oneof them being fixed and crossing the line of sight of the telescope at asuitable angle, and the other being arranged at a suitable angle to thefirst and pivotally connectedwith thebracket, and adifierentially-threaded nut suitably mounted for reg ulating theposition of the pivoted reflector to vary its angle with the fixedreflector, sub stantially as described.

8. The combination with the telescope of a transit or similarinstrument,of abracket revolubly mounted to project beyond the objective of thetelescope, two reflectors mounted on said bracket, one of them beingfixed, and the other being arranged at a suitable angle to the first,and pivotally connected with the bracket, a differentially-threaded nutsuit ably mounted for regulating the position of the pivoted reflectorto vary its angle with the fixed reflector, the said nut having a graduated head, substantially as described and for the purpose set forth.

9. The combination with the telescope of an instrument of the classdescribed, of a bracket mounted to project beyond the objective of thetelescope, two reflectors mounted on said bracket and arranged to form asuitable angle with each other, one of the said reflectors beingpivotally connected with the bracket, a differentially-threaded nutsuitably mounted for regulating the position of the pivoted reflector,the head of said nut being graduated for the purpose set forth, and aspring-held pointer mounted on the bracket and engaging the head of saidnut, substantially as described;

10. The combination with the telescope of a transit or similarinstrument, of a bracket revolubly mounted on the objective extremity ofthe telescope and projecting beyond the same, two reflectors mounted onsaid bracket and arranged at a suitable angle to each other, andsuitableineans for rotating the reflectorcarrying bracket, substantiallyas described.

11. The combination with the telescope of a transit or similarinstrument, of a reflectorholder revolubly mounted on the objectiveextremity of the telescope and projecting forward therefrom, tworeflectors mounted on said reflector-holder and arranged to rotatetherewith, the two reflectors being arranged to form an angle with eachother and also arranged to twice reflect a ray of light, the secondreflection being in line of the optical axis of the telescope, one ofthe reflectors being movably mounted, and a screw mounted on thereflectonholder, to regulate the position ORVILLE F. SHATTUOK.

Witnesses:

DENA NELSON, A. J. OBRIEN.

